The studs are intended to provide traction, having a ground-engaging part of a type suited to the sport involved. Thus, studs for football tend to have relatively sharp ground-piercing spikes, while those for golf shoes currently have relatively soft and blunt ground-gripping spikes. The studs are detachably fastened to the sole of the article of footwear by a screw-threaded spigot on the stud engaging in a correspondingly threaded socket in a receptacle molded in, or otherwise secured to the shoe sole. The screw thread may be single start or multi-start, and the stud and socket may also incorporate a locking ratchet to prevent accidental unscrewing of the stud.
The studs provide most, if not all, of the traction for the footwear and may be of different kinds, even for one sport. Thus, golf studs may have dynamic spikes which flex when pressure is applied to them, or static spikes, which do not flex. A dynamic spike may not always flex in the manner intended, depending on the surface or the way the pressure is applied.
Previously, rotational orientation of the studs relative to the shoe sole was not necessary, as most studs are circular or otherwise rotationally symmetrical. Their final orientation relative to the shoe sole is therefore not relevant.
However, in some sports where the forces on the studs are relatively high and of a particular type, such as lateral forces or forces due to rapid forward acceleration of the wearer of the shoe, studs which are specifically-oriented can be more effective. The term “specifically-oriented stud” will be used to include studs which are non-rotationally symmetrical, or studs which are rotationally symmetrical, but whose orientation relative to the shoe sole is significant. A specifically-oriented stud must be oriented very precisely relative to the shoe sole to ensure that it operates in the desired manner. Most known screw threads and locking ratchets are unable to provide this precise orientation. We have devised a system of ensuring the precise orientation of the stud relative to the receptacle. Orientation of the receptacle in the sole then provides the precise orientation of the stud relative to the sole.